“Save stuff in your inventory and use them whenever you want!”
Was added in the Goat MMO Simulator update on November 20, 2014, afterwards is available from the start.
When you lick an item, you will be prompted to press Baa to save the item to your inventory. Doing so will remove the object from the game world and add it to your inventory. Pressing I opens the inventory, from which you can move items back into the game world. Exiting a map empties your inventory.
In the MMO Simulator, all items in the inventory will be sent to a house in a normally inaccessible area beyond the map's boundaries. To get to this area, you must equip the Gravity Goat mutator and bounce on the blue mushroom near the Goatwind Wall. Turning on anti-gravity right after bouncing will send your goat up very high, making it possible to go over the map boundaries. If you face west, there will be a flat area with a lone house sitting on it. Inside the house are all the items in your inventory, sitting in a large clump.
The same item areas can be found in other maps if equipped. In Goat City Bay you can find one near the dum, where it won't be hidden like in Payday, where inventory items can be found underground near the Police Station and can be only seen via different glitches or Ghost Goat Mutator from Steam Workshop.